ARTICLE VII. 
DESCRIPTIONS OF PLANTS COLLECTED ALONG THE ROUTE, BY W. P. BLAKE, 
AND AT THE MOUTH OF THE GILA. 
BY JOHN T'ORREY. 
Mr. Blake, the geologist of the Expedition commanded by Captain Williamson, having 
requested me to examine and report on the plants that he found in his explorations, as well as 
those collected near Fort Yuma, hy Major Thomas and Lieutenant Du Barry, of the United 
States army, I have prepared the following list. The drawings for the illustrations were made 
by Mr. E. Dwight Church, a young artist of this city, and the engraving was executed hy Mr. 
Prestele. 
JOHN TORREY. 
New York, May 1, 1857. 
Argemone Mexicana, Linn. On the Colorado, and in other parts of California. An extremely 
hispid white flowered variety, which seems to be the same as A. munita, Durand & Hilg. PL 
Herm. 
Nasturtium obtusum, Nutt, in Torr. & Gray, FI. 1, p. 74. With the last, in wet places. 
Flowers through the summer. 
Sisymbrium deflexum, Harv.; Torr. in Bot. Whipp. Rep. Sandy places in the Colorado. 
Varies greatly in size. 
Dithyrasa Californica, Harv. in Hook. Lond. Jour. Bot. 4, p. 77. t. 5 ; Torr. in Bot. Whipp. 
Rep. California desert; March. 
Oligomeris glaucescens, Camb.; Gray, PI. Wright, 2, p. 16. Dry places between the 
Colorado and the sea coast; April, June. 
Sesuvium portulacastrum, Linn ; DC. Prodr. 3, p. 453 ; Var floribus subsessilibus, Gray, PI. 
Wright, 1, p. 13. Flowers on short pedicels. Stamens about 50. Sandy banks of the Colorado. 
Fagonia Californica, Benth. Bot. Sulph. p. 10. Near Fort Yuma. This species is, as 
Bentham remarks, closely related to F. Chilensis and F. Cretica ; hut we think it more closely 
approaches the former than the latter. (Tab. I.) 
Larrea Mexicana, Moricand; Torr. in Emory’s Report, p. 137, t. 0. This is the well known 
Creasote-plant or Creosote bush. It grows from four to six feet high. It is very common in the 
desert west of the Colorado, and in barren spots on the mountains near that river. 
Spileralcea incana, Torr. in Gray, PI. Fendl. p. 23 ; Gray, PL Wright, p. 21. River allu- 
